A Strange Explosion in a Galaxy Billions of Light-Years Away Has Scientists Stumped

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For
a few minutes in October 2014, a mysterious explosion occurred in a galaxy
about 10.7 billion light-years away from Earth. The magnitude of the
explosion was so intense that it produced 1,000 times more energy than all of the stars in its
entire galaxy for the space of a few minutes.

We
learned about this event after scientists took the deepest X-ray image of
our Universe to date from NASA’sChandra Observatory. Researchers narrowed down the
source of the blast with the help of data from the Spitzer and Hubble Space
Telescopes. The small galaxy is relatively faint and unremarkable, located in a
piece of the sky referred to as the Chandra Deep Field South.

Over
the past 17 years, the Chandra X-Ray Observatory has watched this far-flung
galaxy for a cumulative total of 2.5 months, and it has never detected any
evidence of similar events before this unique explosion. Since the event
passed, the galaxy appears to have receded into oblivion once more. Capturing
it at all may have been a lucky break.

Now,
the researchers are poring through the Chandra archive for evidence of similar
events and painstakingly searching data from NASA’s Swift satellite and the
European Space Agency’s XMM-Newton telescope for the same kind of evidence. The
brief duration of the event means that missing other cosmic cataclysms would
have been easy to do. Of course, researchers will also follow up with more
Chandra observations of the galaxy.

A
New Cataclysmic Event

Scientists
know of no
astronomical phenomenon that can explain the behavior. “We may have
observed a completely new type of cataclysmic event,” said
researcher Kevin Schawinski of ETH Zurich in Switzerland. “Whatever it
is, a lot more observations are needed to work out what we’re seeing.”

Via
NASA

Although
they don’t yet have all the answers, researchers do have a few possible
hypotheses that could explain the strange explosion. Of the three primary
ideas, two focus on gamma-ray bursts (GRBs), the brightest known
electromagnetic events that occur in our Universe.

These
super high-energy explosions are released when two neutron stars collide, when
a neuron star and a black hole merge, or when a massive star collapses. When
GRBs are pointing in our direction at the time they occur, they spew a jet of
gamma-rays that later taper into weaker forms of radiation, like X-rays. That’s
how we’re able to detect them.

One
theory to explain this mystery explosion is that we’ve simply picked up a GRB
that was pointed in a different direction, and we don’t recognize what we’re
“seeing.” Another possibility is that we’ve detected a GRB that is actually
past the galaxy we’re observing. A third idea is that we witnessed a black hole
shredding a white dwarf star.

None
of the theories seems like a perfect fit — yet. More data will help explain the
strange explosion, and new technologies like the James Webb Space Telescope, which will replace the Hubble
and collect seven times more light than its predecessor, should help us explain
unique cosmic events like this one.